In Reply to: Re: The Hydraulic Oil Story posted by TheOldHokie on December 29, 2013 at 17:35:23:
Thought the debate was all about UTF being too thin to work as a hydraulic fluid in summer months in warm climates in tractors with worn out hydraulic pumps.
In my opinion if the hydraulic system is working properly, UTF should work at 100F ambient temperature and develop specified minimum output pressure and resulting lifting capacity.
Believe everyone agrees that SAE 80 wt gear oil is difficult to find unless the picker guys from the tv show "pickers" could find some on their escapades.
Choose AW 46 hydraulic fluid to compare to UTF, since it is more common compared to AW 68.
In my opinion if the hydraulics do not work on the tractor might well use a 4X4 jeep.
That is, if the hydraulics do NOT work properly, the tractor is worthless.
On the single grade oils tested at 100C. At 100C there is small difference in viscosity between 80W90, 90, UTF & AW46 and the numbers are useless, except for grading purposes.
Warren Distributing/traveller/TSC is real good about posting the 40C & 100C viscosity for their products. Had to call the chemist to get the numbers on the single grade SAE 90 GL-1 gear oil
Still prefer the SAE 90 over the UTF, but use hydraulics between 50-100F, only.
The multi grade gear oil like 75W90, 80W90, 85W140 are tested for viscosity at 32F
in addition to 100C.
Spoke with service at several JD & NH dealers. All use UTF in the small hypoid differential type tractors.
So the debate still goes on between SAE 90, SAE 80W90 & UTF.
SAE 80W90 costs about 20% more than UTF, non synthetic
Would still clear on the less expensive 303 UTF with lower viscosity and wide spec range viscosity. Probably all right in a hydrostatic drive tractors with rear drop down straight spur gears.
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